The invention relates to a printing machine, such as an office typewriter, in which a printing head device is disposed on a carriage and, more particularly, a fastening arrangement for releasably fastening the printing head to the carriage permitting adjustment of the spacing between the printing head and the cooperating recording medium support.
It is known in printing machines to provide respectively separate operating mechanisms for fastening a printing head to a carriage and for setting the operational spacing between the printing head and the recording medium support. The operating mechanisms for fastening the printing head to the carriage typically, for example, comprise a clamp device with which the printing head is secured to the carriage or, as needed, can be released therefrom. The setting of various spacing distances between the printing head and the cooperating recording medium or print support depends on the thickness of the recording medium being printed, typically paper, and/or on the number of print copies desired. Manufacturing tolerances occurring in the printing head also have an affect on the possible allocation of spacing between the printing head and the cooperating print support. Typically, a basic adjustment is first undertaken which compensates for the manufacturing tolerances and sets a predetermined, defined spacing between the printing head and the cooperating print support. This basic adjustment is carried out by the manufacturing factory and it is a factory adjustment which is difficult for the user or customer to vary. The user or customer can only change the factory adjusted spacing between the printing head and the cooperating print support, which is rigidly preset, by means of makeshift undertakings.
A printing machine having the typical printing head fastening device and employing makeshift customer adjustments exhibits considerable disadvantages. The customer adjustment is usually very involved, since it can frequently be only carried out with auxiliary tools, such as, for example, a wrench for loosening specific parts in the printing machine. As a result, a number of loose parts result which can be easily lost and such action by the customer is time-consuming and cumbersome.
An object of the present invention is to provide a printing head fastening and adjustment system which eliminates the above disadvantages and which can be operated in a simple and intended manner.